A substitution reaction is one in which an atom or functional group attached to a carbon in an organic compound is/are replaced by a different atom or functional group.
i.e: AB + CD ---> AC + BD
This is the only way that a halogen can be added to an alkane:
Substitution reaction : chlorination of methane
Here you can see that the chlorine is replacing a hydrogen in the methane to form methyl chloride.
In a reaction such as butane with chlorine, there are two things that can happen. The result will hydrochloric acid along with either be 1-chlorobutane or 2-chlorobutane depending on which carbon the chlorine attaches to:
1-chlorobutane
2-chlorobutane
Substitution reactions can also occur with benzene: Benzene + Chlorine -----> Chlorobenzene
UV in sunlight is a catalyst for the reaction. The Hydrogen Bromide will turn moist blue litmus paper red.
Bromoethane can still react further, as the other H atoms can still be replaced - Dibromoethane, Tribromoethane and Tetrabromoethane can also be produced.
Chlorine will react with alkanes similarly (as in the other examples above).
Substitution Reactions
A substitution reaction is one in which an atom or functional group attached to a carbon in an organic compound is/are replaced by a different atom or functional group.
i.e: AB + CD ---> AC + BD
This is the only way that a halogen can be added to an alkane:
Here you can see that the chlorine is replacing a hydrogen in the methane to form methyl chloride.
In a reaction such as butane with chlorine, there are two things that can happen. The result will hydrochloric acid along with either be 1-chlorobutane or 2-chlorobutane depending on which carbon the chlorine attaches to:
Substitution reactions can also occur with benzene:
Benzene + Chlorine -----> Chlorobenzene
Another Example:
Ethane + Bromine ---> Bromoethane + Hydrogen Bromide
CH3CH3 + Br2 --------> CH3CH2Br + HBr
UV in sunlight is a catalyst for the reaction. The Hydrogen Bromide will turn moist blue litmus paper red.
Bromoethane can still react further, as the other H atoms can still be replaced - Dibromoethane, Tribromoethane and Tetrabromoethane can also be produced.
Chlorine will react with alkanes similarly (as in the other examples above).
Sources:
http://en.wikipedia.org/wiki/Substitution_reaction
http://www.campusrn2rn.com/video/2096231:Video:14621
http://www.chalkbored.com/lessons/chemistry-12/organic-synthesis-worksheet.pdf